1. Field of the Invention
The present invention relates to a structure, an electron emitting device, a secondary battery, an electron source, and an image display device each of which uses carbon fibers.
2. Description of the Related Art
In recent years, field emission type electron emitting devices include an electron emitting device using carbon fibers as electron emitting bodies. Because of such a field enhancement effect resulting from shape that is produced by using carbon fibers as electron emitting bodies, the electron emitting device using carbon fibers as electron emitting bodies can emit electrons from the electron emitting bodies in a lower electric field intensity than an electron emitting body made of carbon or the like shaped like a film (in the shape of a plane).
Methods for forming carbon fibers used for electron emitting bodies include a method for applying carbon fibers prepared in advance to the surface of an electrode (cathode electrode), a method for vapor-depositing carbon fibers by the use of an electrode (cathode electrode) having catalytic particles placed on the surface thereof, and the like. In the case of forming carbon fibers by the vapor deposition method, it is necessary to consider the electric and physical connection between the carbon fibers and the electrode (cathode electrode). Moreover, it is preferable that a material having high conductivity is used as the electrode (cathode electrode), so that there is proposed a method for placing another conductive body (supporting member) different from the electrode (cathode electrode) on the electrode (cathode electrode) and further placing catalytic particles on this supporting member and then forming carbon fibers by a vapor deposition method.
In a Japanese Unexamined Patent Publication No. 11-139815 is disclosed a technology that places a film, which is formed by dispersing catalytic ultra-fine particles containing at least one metal selected from Fe, Co, and Ni into a material whose main component is at least one metal selected from Cu, Ag, Au, and Cr, on a substrate made of Si or the like and vapor-deposits carbon nanotubes by the use of the above-mentioned catalytic particles.
Moreover, in the Japanese Unexamined Patent Publication No. 2002-289087 is disclosed a technology that places a member on an electrode (cathode electrode) and vapor-deposits carbon nanotubes on this member by the use of catalytic particles. It is disclosed that a nitride of at least one element selected from Ti, Zr, Ta, and Nb, an oxide of at least one element selected from Ti, Zr, Ta, and Nb, or a mixture of the nitride and the oxide is used as the supporting member of the carbon fibers.